54 Knud Jessen. 



closed at night, and this makes self-pollination possible. 

 Poppius found the flowers to be slightly protandrous at 

 Esbo in Finland; they were very sparsely visited by insects. 

 Concerning the fruits see p. 48. 



Sibbaldia procumbens L. 



Lit. Warming, 1886, a. Lindman, 1887. Hartz, 1895, a. 

 Norman, 1895. A. Cleve, 1901. Kjellman, 1901. Sylvén, 

 1906. Hollstein, 1907. 



This species grows in grassy and often somewhat damp 

 localities, not, however, in bogs (Cleve). It is circumpolar, 

 and occurs also in Great Britain, Iceland, the Færoes and 

 the Alps. 



The alcohol material was collected in Spitzbergen and 

 in Greenland, in different places. 



According to Sylvén the seedling has a slender, slightly 

 branched main root which together with the hypocotyl 

 quickly becomes woody. From the leaf-axils of the first 

 young rosette monopodial lateral shoots are developed sooner 

 or later, which in the course of time may attain a considerable 

 length; they become prostrate and have a somewhat up- 

 wardly turned apex. The primary root may live for a long 

 time, and in the museum of the Botanic Garden in Copen- 

 hagen tufts are found, 20 — 30 cm. in diameter, the numerous, 

 closely placed shoots of which are still in connection with 

 the vigorous main root. Kjellman (1. c.) writes that Sibbaldia 

 either does not develop adventitious roots or does so only 

 very slightly; but this statement does not quite agree with 

 the specimens I have seen in the herbarium mentioned above; 

 to judge from the latter, adventitious roots — even vigorous 

 ones — may be fairly often developed from older branches, 

 and the plant is certainly not dependent on its primary root, 

 but has some power of vegetative propagation. The shoots are 



